Waltham Weather in September

Waltham in September averages 24°C (75°F) during the day and 12°C (54°F) at night. This is the driest month of the year.

Rainfall in Waltham in September

Conditions tend to be dry and settled, making it a good month for outdoor plans. Rain is expected on roughly 9 days, totalling around 83 mm (3.3 in) for the month. When showers do arrive, they tend to be on the heavier side. Worth being prepared even if rain days are not that numerous.

Temperature in Waltham in September

If you're visiting Waltham in September, expect perfect temperatures with highs of 24°C (75°F) and overnight lows of 12°C (54°F). This gives the month a fairly typical daily rhythm, with warmer afternoons and more comfortable nights. At 12°C (54°F) overnight, it can feel quite a bit cooler after dark. Worth packing something warmer for evenings, but the cooler temperatures are ideal for sleeping.

Sunshine in Waltham in September

The city usually sees around 238 hours of sunlight, indicating many sunny days — a great month for sightseeing.

Wind Speed in Waltham in September

September has wind speeds averaging 5 m/s (10 knots). You can expect gentle to moderate winds that move small trees and make flags wave steadily on typical days. Conditions typically range from light breezes to moderate winds.

Average water temperature in September

With water at 18°C (64°F), swimming is comfortable for most people. It feels refreshing rather than cold, though it depends a bit on personal preference.

Our weather planner can help you find worldwide destinations with pleasant weather during this period. May, August and September typically offer the best weather for Waltham.

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit the United States of America, check out our Waltham's climate page.

Waltham Temperature in September

Min Temperature 12°C (54°F)  

Max Temperature 24°C (75°F)  

Water Temperature 18°C (64°F) *  

Chance of Rain 30%  

Precipitation 83 mm (3.3 in)  

Rainy days 9 days  

Humidity 69% *  

Windspeed 5 m/s (10 knots) *  

Sunshine 238 hours *  

Percentage Sunshine 63% *  

* Data from: Boston, the United States of America (16 KM, 10 Miles).

What to Wear in Waltham in September

For Waltham in September, you'll want flexible clothing. It's wise to pack cotton shirts, comfortable shorts, and a pair of jeans for cooler evenings. A light sweater or jacket is useful for air-conditioned spaces (like buses) or unexpected cool moments. High rain levels are expected, so pack waterproof gear and an umbrella or poncho. The water temperature sits at about 18°C (64°F), which is too chilly for most people to enjoy swimming. Leave the swimsuit at home unless you love cold water. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.

What To Do in Waltham in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

9/10

Cycling

9/10

Walking

9/10

Barbeque

8/10

Camping

8/10

Outdoor sports

9/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit the United States of America, check out our Waltham's climate page.

More climate data for Waltham

Temperature Rainfall Sunshine Humidity Wind Speed Water Temp

See the full Waltham climate overview or explore weather in the United States of America.